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([2a09:80c0:192:0:5dac:bf3d:c41:c3e7]) by smtp.gmail.com with ESMTPSA id p7-20020adff207000000b00313f031876esm1301923wro.43.2023.07.06.01.55.37 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Thu, 06 Jul 2023 01:55:37 -0700 (PDT) Message-ID: <492be1c2-9078-1923-51f9-e01156455ea1@redhat.com> Date: Thu, 6 Jul 2023 10:55:37 +0200 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.12.0 Subject: Re: [PATCH] mm/ksm: prepare to remove the redundant ksm_merging_pages in procfs To: Nanyong Sun , akpm@linux-foundation.org Cc: xu.xin16@zte.com.cn, wangkefeng.wang@huawei.com, linux-kernel@vger.kernel.org, linux-mm@kvack.org References: <20230706094917.588213-1-sunnanyong@huawei.com> From: David Hildenbrand Organization: Red Hat In-Reply-To: <20230706094917.588213-1-sunnanyong@huawei.com> X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Language: en-US Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Rspam-User: X-Stat-Signature: y895ek5uinxjhm9uj6a8ikjdw4ae9wzb X-Rspamd-Server: rspam07 X-Rspamd-Queue-Id: F01531C0002 X-HE-Tag: 1688633741-245177 X-HE-Meta: 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 rd6n+QXy UiftJ2O76TpwiixcOcJm0IdgM7IGIMn+f3oMINcYP7eOJ/KtpjL1Cm3K3iwPvkidmmF9L3FvcYynhyGOoiZ3CRi1a+3xRjzO0aH0/YTMPcglv0cABr0iGNToakpbAPU/mbYt36BuRCgrgnqvZBAzfUVeYdGzsqf0hP9GwzlZZXqvn++Ay8VNQkFX40Dvb9MWVapmJigQUJSZfyn5t2mJSU/xQ+nt/ujQiYFefL/bTDzJr0oG2bgapf7bhUC36N3tZRXWYDMxBmVYl1Ln0B82wOvCZV3pOAiv/3EMWmajaO4w+aREebXCzOYgjnXra+H9beOCuFxbdkd0hUWbJl4ZyJ/ZNvXCxvFB/Irpq4ohYT32C8EOkUFEHJzTIs8N+TPQlvH/5z/rWdj5JBQs2D25z78TsPgfGPVtiCeSUWtprVgDsFhlEZ7uoPt4ktKCS4TGAqMnKZ/JitX5sTVoMIt3LTdyCGioveLgy8je/ X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On 06.07.23 11:49, Nanyong Sun wrote: > Since the ksm_merging_pages information already included in > /proc//ksm_stat, we could remove /proc//ksm_merging_pages > to make the directory more clean, and can save a little bit resources. > > To delete this interface more smoothly and avoid userspace break, > retain this interface temporarily and modify its function to hint > users to use ksm_stat instead. > > Signed-off-by: Nanyong Sun > --- > fs/proc/base.c | 9 +-------- > 1 file changed, 1 insertion(+), 8 deletions(-) > > diff --git a/fs/proc/base.c b/fs/proc/base.c > index eb2e498e3b8d..d080c58cbe6c 100644 > --- a/fs/proc/base.c > +++ b/fs/proc/base.c > @@ -3189,14 +3189,7 @@ static int proc_pid_patch_state(struct seq_file *m, struct pid_namespace *ns, > static int proc_pid_ksm_merging_pages(struct seq_file *m, struct pid_namespace *ns, > struct pid *pid, struct task_struct *task) > { > - struct mm_struct *mm; > - > - mm = get_task_mm(task); > - if (mm) { > - seq_printf(m, "%lu\n", mm->ksm_merging_pages); > - mmput(mm); > - } > - > + seq_puts(m, "please use /proc//ksm_stat instead\n"); > return 0; > } > static int proc_pid_ksm_stat(struct seq_file *m, struct pid_namespace *ns, Why do we care so much about removing 15 simple LOC? That change here will already mess with user space. Sorry, but IMHO it's all not worth the churn. -- Cheers, David / dhildenb